Windows XP/Vista, DirectX 9.0 drivers.
Publisher's description of Thirdbrush
A powerful tool to paint on 3D models as easily as on a sheet of paper. Use your mouse or stylus to texture any 3D objects in some minutes. That your are an experimented designer or a simple young game creator, Thirdbrush will change the way you work for ever. Version 1.2 adds brushes.